1. Field of the Invention
This invention relates generally to a nozzle cap threadedly engaged with a distal end of a nozzle, and more particularly to such a nozzle cap threadedly engaged with a nozzle which is used to charge an air conditioner with a refrigerant.
2. Description of the Related Art
Conventional nozzle caps comprise a thread adapted to be threadedly engaged with a distal end of a nozzle and a terminal wall provided at a proximal end side of the thread so that the distal end of the nozzle is butted against the proximal end. A sealing member provided on the terminal wall is closely adhered to the distal end of the nozzle so that the nozzle cap seals an opening of the nozzle. Such a sealing member is shown by reference numeral 12 in JP-A-2001-287521 or by reference numeral 24 in JP-A-5-312439.
In the above-described nozzle cap, the sealing member is merely placed on the terminal wall or simply engaged with the thread. Accordingly, there is a possibility that the sealing member may separate from the body of the nozzle cap. The assignee of the present application examined the cause for separation of the sealing member and found that the sealing member, when pressed against the nozzle, adhered to the nozzle. When the nozzle cap is disengaged from the nozzle, the sealing member separates from the thread of the cap to remain at the nozzle side. Particularly in the nozzle cap used for a nozzle through which a high pressurized fluid such as an air conditioner refrigerant, the sealing member is subjected to a large inner pressure to be pressed against the nozzle, thereby adhered to the nozzle. Thus, the sealing member cannot be prevented from separation in the conventional nozzle caps.